(a) FIELD OF THE INVENTION
This invention relates to a process for producing L-threonine by fermentation.
(b) PRIOR ART
It hitherto has been known that the microorganism belonging to the genus Proteus or Providencia of which the mutant requires L-isoleucine, can be used as microorganisms capable of producing L-threonine by fermentation (Japanese Examined Patent Publication No. 4440/1968).
However, there is room for further improvement in the capability of the strains as to the amount of L-threonine accumulated and as to the yield of L-threonine from the starting material such as glucose or fructose.